Packing gasket and method of making same



March 12, 1929. T, m rr 1,705,455

PACKING GASKET AND METHOD OF MAKING $AIE Original Filed Adg. 25. 192'? 2Shoots-Sheet l Inueior:

Richard]? Gnzfflifim by mm M [M An a.

March 12, 1929. r mm-ms 1,705,455

PACKING GASKET AND METHOD OF MAKING SAME Original Filed Aug. 25, 1927 2Sheets-Sheet 2 Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE,

RICHARD T. GRIFFITHS, OI! AKRON, OHIO, ASSIGNOR TO THE MILLER RUBBERCOM- PANY, OF AKRON, OHIO, A. CORPORATION OF OHIO.

PACKING GASKET AND METHOD OF MAKING- SAME.

Original application filed August 25, 1927, Serial No. 215,438. Dividedand this application filed August 25, 1928. Serial No. 302,070.

My present invention relates to an improved packing gasket, and includesmatter divided out of an application filed b'y me In the U. S. PatentOlliee on the 25th day of understood, refereneeis made to theaccompanying drawings in which:

Fig. 1 is a perspective view showing a portion of a refrigerator door byway of example) and the manner in which my 1mproved packing strip isapplied thereto.

Fig. 2 is a transverse section through the I strip on a line with one ofthe attaching devices.

Fig. 3 is a sectional view showing the manner of applying the strip.

Fig. 4 is a fragmentary section of mold showing the method of formingthe strip.

Fig. 4 is a transverse section thereof.

Fig. 5 is a perspective view of one of the discs used to form theattaching means.

Fig. 6 is a sectional detail of a modified form of attaching means.

Fig. 7 is a similar view of a further modification.

Fig. 8 is a till further modification.

Figs. 9 and 10 are detail views illustrating the method of manufacturingthe article of Fig. 7 and Fig. 11 is a detail view illustrating themethod of making the article of Fig. 8.

Referring by reference characters to this drawing, the numeral 1designates a closure member of the swinging type such as a metalrefrigerator door having the flange portion 1 to which the packing stripis to be secured.

This is provided with a plurality of holes 1 spaced apart distancesaccording to circumstances or as may be found most desirable.

2 designates the packing strip or gasket of sponge rubber and mostdesirably made of semi-cylindrical shape.

At distances corresponding to the spacing of the holes 1", the flat faceof the gasket is provided with attaching devices in the shape of buttonsor projections, each comprising a shank 3 of solid soft rubber and adiameter corresponding approximately to the diameter of opening 1", andenlarged head or flange 3 of a flexible character. Given such aconstruction, I have found that by the use of-a suitable tool such asindicated at 4, the strip including its attaching means may be sodistorted from normal condition as to allow the flexible flange 3 to bepoked or pushed through the opening 1 whereupon its inherent resiliencewill cause it to draw the flat face of the gasket into contact with thecarrying plate and hold it firmly in position.

I have found that by making the attaching members of hollow form asshown in Fig. 3, the connection above described is facilitated. Suchconstruction aids in economical manufacture by the following methodwhich I have devised.

In Fig. 4, I have shown conventionally and in fragmentary form a threepart mold comprising a lower or main member 8 having a mold cavity 8 ofa shape conforming to the shape of the desired packing strip or gasket,a top member 7 and an intermediate member 6 having an openingtherethrough the lower portion 6 of which is of a diameter correspondingto the diameter of the stem 3 of the attaching member while the upperpart 6 is countersunk or of a diameter corresponding to the head 3 ofsaid attaching member. A length of unvulcanized sponge rubber compoundof a size insufficient to fill the cavity 8 is placed therein, moldmember 6 applied, and a disc 3* of unvulcanized or partially vulcanizedsoft solid rubber compound (see Figs. 4 and 5), is placed in the rebatedor countersunk portion 6" after which the top plate 7 is applied and themold subjected to heat in the customary manner.

The heat softens the rubber disc which tends to sag into the opening andbe pressed further therein by air or gases entrapped above the disc. Asthe heat is continued the sponge rubber compound expands by reason ofthe blower therein until it fills the mold cavity and contacts with thedepressed portion of the disc or discs and the sponge rubber strip andcupped disc members are by the further heat vulcanized together into asingle'unitary o'r homogeneous article of the shape shown in Figsl and2.

Instead of making the button or attaching means of hollow form as abovedescribed, I

according to this figure, I provide a three 3 part mold as shown in Fig.9 comprising top, bottom, and intermediate plates 9, 10, and 11,respectively, having a mold cavity of the shape of the attaching memberor button and having a core pin 11 carried by the-upper plate anddepending into the cavity, it being understood of course that inpractice the mold would have a large number of such cavities for moldinga plurality of articles in a single operation.

Sufficient rubber having been placed in each cavity to just fill thesame when the mold is .closed, the closed mold is subjected tosuflicient heat to partially vulcanize the button or buttons, whereafterthe mold plate -11 is removed and placed between the mold plates 12 and13, the latter having a mold cavity 13 corresponding to the cavity 10while the plate 12 has a cavity 12 corresponding to the desired shape ofgasketstrip.

The mold being subjected to proper heat, the sponge rubbercompound shownin the cavity expands and contacts with and surrounds the base flange ofthe button and projects part way into the hollow shank and is firmlyunited thereto.

.As a further modification, I may make the gasket strip and attachingmeans all-off sponge rubber as indicated at 3, Fig. 8, which may beaccomplished by placing in the gasket cavity 14 of mold member 14:.sufficient sponge rubber compound to cause the rubber to be forced intothe recesses which form the attaching members, said recesses being ofthe proper shape as indicated in connection with Fig. 7. It will beunderstood that the mold vulcanization produces a skin on the spongerubber which gives requisite strength, but further stren th or stiffnessmay be imparted to the attaching means b molding therein a reinforcesuch as a tac d laced in the mold cavity and surrounded y the spongerubber as it expands.

If desired, the mold of Fig. 9 may be a separate mold from that of Fig.10 as an entirety, with the button forming cavities set closely togetherto increase capacity and the buttons thereafter transferred to anotherplate 11, Fig. 10, with the holes spaced apart the proper distance forgasket attachment. Having thus described my invention, what I claim is:l v

1. A packing gasket comprising a strip of cellular rubber havingrelatively stiff rubber attaching buttons homogeneously united thereto.

2. A packing gasket comprising an elongated strip of cellular rubberhaving an imperforate skin and a plurality of relatively stifi rubberattaching buttons homogene-

